Abstract

The hydrography of the Brazil/Guiana shelf is strongly influenced by freshwater run-off from major river systems extending from the Amazon on the northeast coast of Brazil to the Orinoco in Venezuela and the Gulf of Paria. Sediment, carbon and organic loads in freshwater discharge have a profound influence on the bathymetry and productivity of coastal habitats.\Four species of penaeid shrimp predominate commercial landings along the Brazil/Guiana continental shelf. Their recruitment into the commercial fishery appears to be influenced by coastal habitat type, environmental conditions (e.g. precipitation, temperature), freshwater runoff from river systems as well as biotic factors. Shrimp display considerable variation in seasonal and annual abundance. Much of this variability appears due to mortality during the planktonic larval and subsequent demersal estaurine juvenile stages when environmental factors are expected to determine cohort strength. These fluctuations, and the ability to predict them, are of interest to commercial large and small scale fishermen and resource managers. Traditional methods of stock assessment have proved inadequate, and more recent techniques that attempt to incorporate a series of environmental parameters have met with limited success. This study reviews the major factors affecting shrimp recruitment and production, and proposes monitoring methods and ecological approaches which may allow us to improve o ut understanding of the processes determining yields and our ability to predict them.

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